The present invention relates generally to agricultural implements, and more particularly to a planter or similar implement designed to be towed behind a work vehicle, and that is equipped with a seed distribution system.
A wide range of agricultural implements are known and are presently in use, particularly designed for towing behind a work vehicle, such as a tractor. In one family of such implements, including tillers, planters, and so forth, a wide swath of ground can be tilled, planted, or otherwise worked in each pass of the implement in a tilled or untilled field. Planters, for example, often include frames supported by series of wheels and a tool bar extending transversely with respect to a line of movement of the implement across the field. Seed tanks are typically supported on the implement support structure, such as just forward of or over the tool bar. Large amounts of seed may be poured into these tanks and, as the implement is advanced across the field, seeds are transferred from the tanks by the distribution system connected to the row units. Attached to the tool bar are a series of row units for dispensing seeds in parallel rows either in tilled or untilled soil. Row units may contain various mechanical components to facilitate seed distribution such as a seed wheel and other mechanisms. These mechanisms help regulate seed population and set seed spacing in the soil.
Seed distribution mechanisms are typically driven via sprockets and chains using a ground-contacting drive wheel or a hydraulic motor as their prime movers. Sprocket and chain mechanisms require tedious adjustments and maintenance by the operator, including frequent lubrication. The operator may be required to manually adjust and move the chain between differently sized drive sprockets in order to achieve a desired geometry, resulting in proper seed distribution. A loose chain will result in inefficient drive motion transfer from the wheel or motor to the driveshaft. Moreover, efficiency of the mechanism may be reduced by debris that may interfere with the chain-sprocket connection. While this, in certain situations, may not pose particular problems, it requires additional maintenance and adjustment, such as regular tightening of the chain-sprocket mechanisms.
There is a need, therefore, for improved seed drive mechanisms in planters that are more efficient and require less maintenance. There is a particular need for seed drive mechanisms that reduce or eliminate the use of chains and sprockets.